A crowd calling for a link between vaccines and autism flooded the streets of Brisbane, Queensland today in a plea to quell a measles outbreak.

But furious anti-vaxxers pelted crowds with rocks, stones and sticks, targeting journalists and the anti-vaccination movement.

Security guards were forced to break up the melee, and the scene was quickly cleared.

The horrific incident erupted as organisers of the event – which is part of Australia’s National Vaccine Awareness Week – were handed loudspeakers urging people to vote for a YouGov poll to find out if they were pro-councillor, pro-pro-vaccine or pro-toxine, the weekly federal election begins on September 24.

Two gasps greeted speakers before a speaker called for a mass walkout of polio vaccinations from public schools.

The tragedy and shame of Baby P forced the organisers to concede the decision to stage the event.

But there was a worry about it receiving another offensive backlash.

Anti-vaxxers apparently hacked the online page of the health department to inject an opinion article on the issues.

Police arrived at a rally in Goulburn Road, in Paddington, where about 300 people gathered.

Police were already called when reports of a violent confrontation arose, and eventually three people were arrested, including the head of public affairs, Ms Elia.

As police moved in to break up the protest, an anti-vaxxer was taken from his car who climbed on top of a police vehicle and was taken away by another person.

Two riot police vans were set alight in the melee.

Opposition Leader Bill Shorten urged supporters to “stop talking about the facts”, while Mr Wright said the government had “ignored this outbreak”.

A tense crowd, including toddlers and an ill one, was left with many months of hope for a legalisation of all vaccinations.

“We have at least 80 per cent research, at least 80 per cent evidence, that we should be immunising our kids,” Ms Wright said.

“There is no excuse not to immunise kids.”

She said an alternative view on vaccines needed to be addressed.

“On legalisation, as a Liberal Party MP I didn’t want to be part of it,” Ms Wright said.

“We want that debate to be done but one that does not vilify kids for being vaccinated.”

In New South Wales, opposition Labor MLC Sam Dastyari proposed an amendment to protect children under 18 from the developmentally delayed exemption.

But the proposed amendment was rejected as it was lodged by the opposition’s NSW Health spokeswoman, Jodi McKay.

She said the video showed what could happen if the proposed amendment was voted on this week.

Ms McKay said the proposed amendment would look at the approved and unrecognised.

“That’s the safety issue,” she said.

“This is not a vote on tolerance.”